cfg.External = map[string]string{}
	cfg1.External = cfg.External
	if imports(f, "C") {
		// Run cgo on gofmtFile(f)
		// Parse, extract decls from _cgo_gotypes.go
		// Map _Ctype_* types to C.* types.
		err := func() error {
			txt, err := gofmtFile(f)
			if err != nil {
				return err
			}
			dir, err := os.MkdirTemp(os.TempDir(), "fix_cgo_typecheck")
			if err != nil {